Simulating the diversity of shapes of the Lyman-$\alpha$ line

Abstract

The Ly$\alpha$ line is a powerful probe of distant galaxies, which contains information about inflowing/outflowing gas through which Ly$\alpha$ photons scatter. To develop our understanding of this probe, we post-process a zoom-in radiation-hydrodynamics simulation of a low-mass ($M_{\ast }\sim 10^9{M}_{\odot }$) galaxy to construct 22500 mock spectra in 300 directions from $z=3$ to 4. Remarkably, we show that one galaxy can reproduce the variety of a large sample of spectroscopically observed Ly$\alpha$ line profiles. While most mock spectra exhibit double-peak profiles with a dominant red peak, their shapes cover a large parameter space in terms of peak velocities, peak separation and flux ratio. This diversity originates from radiative transfer effects at ISM and CGM scales, and depends on galaxy inclination and evolutionary phase. Red-dominated lines preferentially arise in face-on directions during post-starburst outflows and are bright. Conversely, accretion phases usually yield symmetric double peaks in the edge-on direction and are fainter. While resonant scattering effects at $<0.2\times R_{\mathrm{vir}}$ are responsible for the broadening and velocity shift of the red peak, the extended CGM acts as a screen and impacts the observed peak separation. The ability of simulations to reproduce observed Ly$\alpha$ profiles and link their properties with galaxy physical parameters offers new perspectives to use Ly$\alpha$ to constrain the mechanisms that regulate galaxy formation and evolution. Notably, our study implies that deeper Ly$\alpha$ surveys may unveil a new population of blue-dominated lines tracing inflowing gas.

Accepted for publication in MNRAS

References in corpus (43)

• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• The MUSE second-generation VLT instrument
• A New Calculation of the Ionizing Background Spectrum and the Effects of HeII Reionization
• The effect of massive binaries on stellar populations and supernova progenitors
• 3D Lyman-alpha radiation transfer. I. Understanding Lyman-alpha line profile morphologies
• Escape fraction of ionizing photons during reionization: effects due to supernova feedback and runaway OB stars
• Using Lyman-alpha to detect galaxies that leak Lyman continuum
• Building Merger Trees from Cosmological N-body Simulations
• Lyman-alpha spectral properties of five newly discovered Lyman continuum emitters
• Observations of the Lyman-$\alpha$ Universe
• Feedback-regulated star formation and escape of LyC photons from mini-haloes during reionisation
• The MUSE Hubble Ultra Deep Field Survey: II. Spectroscopic redshifts and comparisons to color selections of high-redshift galaxies
• The Low-Redshift Lyman Continuum Survey II: New Insights into LyC Diagnostics
• Galaxies that Shine: radiation-hydrodynamical simulations of disk galaxies
• Lyman alpha Resonant Scattering in Young Galaxies - Predictions from Cosmological Simulations
• The COS Legacy Archive Spectroscopy SurveY (CLASSY) Treasury Atlas
• The Sunburst Arc: Direct Lyman α escape observed in the brightest known lensed galaxy
• The THESAN project: Lyman-alpha emission and transmission during the Epoch of Reionization
• Lyman alpha Radiative Transfer in Cosmological Simulations using Adaptive Mesh Refinement
• LyC escape from SPHINX galaxies in the Epoch of Reionization
• Lyman alpha emission in high-redshift galaxies
• Diverse properties of Ly-alpha emission in low-redshift compact star-forming galaxies with extremely high [OIII]/[OII] ratios
• The MUSE Hubble Ultra Deep Field Survey XIII. Spatially resolved spectral properties of Lyman alpha haloes around star-forming galaxies at z > 3
• Mapping Neutral Hydrogen During Reionization with the Ly-alpha Emission from Quasar Ionization Fronts
• From Mirrors to Windows: Lyman-Alpha Radiative Transfer in a Very Clumpy Medium
• A Comprehensive Study of Ly$\alpha$ Emission in the High-redshift Galaxy Population
• Kinematics and Optical Depth in the Green Peas: Suppressed Superwinds in Candidate LyC Emitters
• Modeling $237$ Lyman-$\alpha$ spectra of the MUSE-Wide survey
• An extreme blue nugget, UV-bright starburst at z=3.613 with ninety per cent of Lyman continuum photon escape
• Lyman-$\alpha$ as a tracer of cosmic reionisation in the SPHINX radiation-hydrodynamics cosmological simulation
• NIHAO XIX: How supernova feedback shapes the galaxy baryon cycle
• The physics of Lyman-alpha escape from disc-like galaxies
• UV absorption lines and their potential for tracing the Lyman continuum escape fraction
• Radiation-MagnetoHydrodynamics simulations of cosmic ray feedback in disc galaxies
• A systematic study of the escape of LyC and Ly$\alpha$ photons from star-forming, magnetized turbulent clouds
• Lyα emission from galaxies in the Epoch of Reionization
• The MUSE eXtremely Deep Field: Individual detections of Lyα haloes around rest-frame UV-selected galaxies at z~2.9-4.4
• MgII in the JWST Era: a Probe of Lyman Continuum Escape?
• Lyman Alpha and MgII as Probes of Galaxies and their Environments
• Gas flows in the circumgalactic medium around simulated high-redshift galaxies
• A double-peaked Lyman-$\alpha$ emitter with a strong blue peak multiply imaged by the galaxy cluster RXC J0018.5+1626
• LESSER: A Catalogue of Spectroscopically selected sample of Lyman-$\alpha$ Emitters Lensed By Galaxies
• The Lyman Alpha Spectral Database (LASD)

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• Mapping reionization bubbles in the JWST era I: empirical edge detection with Lyman alpha emission from galaxies
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• A galactic outflow traced by its extended Mg II emission out to a $\sim 30$ kpc radius in the Hubble Ultra Deep Field with MUSE
• Spatially-resolved Spectroscopic Analysis of Ly$\alpha$ Haloes: Radial Evolution of the Ly$\alpha$ Line Profile out to 60 kpc
• The Lyman-alpha and Continuum Origins Survey. I. Survey description and Ly$\alpha$ imaging
• The MUSE Extremely Deep Field: Classifying the Spectral Shapes of Lya Emitting Galaxies
• SIMPLE: Simple Intensity Map Producer for Line Emission
• Ionizing Radiation Escape from Low-Redshift Galaxies and Its Connection to Cosmic Reionization
• The Lyman-alpha and Continuum Origins Survey II: the connection between the escape of ionizing radiation and Lyman-alpha halos in star-forming galaxies
• A public grid of radiative transfer simulations for Lyman-alpha and metal lines in idealised galactic outflows
• A Simulated Galaxy Laboratory: Exploring the Observational Effects on UV Spectral Absorption Line Measurements
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• Modelling LAEs in the Epoch of Reionization with OBELISK
• The Intrinsic Distribution of Lyman-$\alpha$ Halos
• QSO MUSEUM III: the circumgalactic medium in Ly$\alpha$ emission around 120 $z\sim 3$ quasars covering the SDSS parameter space. Witnessing the instantaneous AGN feedback on halo scales
• Spectral reconstruction for radiation hydrodynamic simulations of galaxy evolution
• Radiative Transfer Simulations of Ly$\alpha$ Intensity Mapping During Cosmic Reionization Including Sources from Galaxies and the Intergalactic Medium
• A resolved Lyman-Alpha profile with doubly peaked emission at z~7
• Double-Peaked Ly$\alpha$ Emission during Reionization Requires Nearby Voids and a Favorable Local Ionizing Background
• Constraining the geometry of the gas surrounding a typical galaxy at $z=3.4$ with Ly$\alpha$ polarization